Magnetic resonance imaging machines (MRI machines) are now used extensively in hospitals and MRI centers in order to enable physicians to view cross-sections of patients'anatomy. These machines are very expensive to purchase and cost in the range of $2 million dollars each, depending on field strength. In order to rapidly recover the expense of this investment, the desired practice is to use these machines 8-24 hours a day, cycling patients in and out of the machines in increments of about 1 hour or less. With currently available software, the cycle time has been reduced to about 25 minutes. In addition to the pressure imposed by the need to recover the large initial investment, there is pressure to utilize the machines as much and as quickly as possible since each MRI scan costs a patient or insurer in the neighborhood of $1000, not including a radio-logist's fee of $250 to $300. Accordingly, any time that the machine is not being used, it appears that the organization owning or leasing the machine is losing money.
The medical problems confronting patients scanned by MRI machines cover the gambit from fractured bones to cancer, from AIDS to tuberculosis. The environment of an MRI machine is friendly to infectious agents because the bore has a diameter in the range of 54 to 60 cm, and can become warm and with an environment which promotes a bacteria growth. Since patients remain in the machine for 25 to 45 minutes while breathing and perhaps perspiring, these machines can become coated with bacteria and viruses. On occasion, patients sneeze, cough, vomit, urinate or defecate while confined in the bore of an MRI machine. While these events may not be injurious to the technologist performing them, subsequent patients may find themselves in substantial peril. For example, a patient's gown could be wet from their own urine and coat the wall of the bore which could unknowingly transmit a disease to the next patient.
This peril poses a substantial health problem. Recognizing the problem creates a reason to develop a protocol for sanitizing MRI machines. Still, the problem remains and is readily apparent to the health care technologists who operate the machines and observe and cope with the infectious events.
Occasionally, patients may find themselves in the bores of MRI machines proximate readily apparent residue of previous infectious events which residue has not been removed by a technologist. They will then complain vehemently of the situation in which they find themselves. The scanning procedure must then be terminated, the patient withdrawn from the bore and the visible, noxious material removed before the patient can be reintroduced into the bore. Having been previously revolted, it may be difficult to persuade the patient to reenter the bore. This, of course, can disrupt scheduling. When a patient causes a major infectious event, it may take 15 or 20 minutes to clean the MRI machine, requiring the MRI technologist or some other unfortunate employee to climb into the bore in order to clean the bore which, to say the least, increases the chance of the technologist contracting a disease.
For the foregoing and other reasons, it is a feature of the present invention to provide methods and apparatus for sanitizing MRI machines after each patient has been scanned, or at least when obviously necessary.